SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd393a8148a11cfd4bd78d06203ce3199c41b9c285688e9ad0fbfc396de1df774' 
  AND token = 'O+GKnMa5MqpFCYZcnEmd2I1sVhuhZ09XQd+RG8Nz3ew=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}